NASA to explore possibility of beamed energy propulsion for space launch

WASHINGTON - NASA is conducting studies to examine whether beamed energy propulsion can be used for launching crafts in space.

A beamed thermal propulsion system would involve focusing microwave or laser beams on a heat exchanger aboard the rocket. The heat exchanger would transfer the radiation’s energy to the liquid propellant, most likely hydrogen, converting it into a hot gas that is pushed out of the nozzle.

“The basic idea is to build rockets that leave their energy source on the ground,” Fox News quoted Jordin Kare, president of Kare Technical Consulting, as saying.

“You transmit the energy from the ground to the vehicle.”

As the beam shines on the vehicle continually, it would take 8 to 10 minutes for a laser to put a craft into orbit, while microwaves would do the trick in 3 to 4 minutes.

Any launch system would be built in high-altitude desert areas, so danger to wildlife shouldn’t be a concern, Kare says.

Thermal propulsion systems are also safer than chemical rockets since they can’t explode and don’t drop off pieces as they fly. They are also smaller and lighter because most of the complexity is on the ground, which makes them easier and cheaper to launch.

Another advantage is that you can add more energy externally, which means a spacecraft can gain a certain momentum using less than half the amount of propellant of a conventional system, allowing more room for the payload.

“Usually in a conventional rocket you have to have three stages with a payload fraction of three percent overall,” says Kevin Parkin, leader of the Microwave Thermal Rocket project at the NASA Ames Research Center.

“This propulsion system will be single stage with a payload fraction of five to fifteen percent.”

There is a limitation, however - according to Kare, it would require a very large, expensive laser.

But you could buy commercially available lasers that fit on a shipping container and build an array of a few hundred.

“Each would have its own telescope and pointing system,” he says. “The array would cover an area about the size of a golf course.”

Beamed energy propulsion would be useful for putting microsatellites into low Earth orbit, for altitude changes or for slowing down spacecraft as they descend to Earth. But the technology could in the future be used to send missions to the Moon or to other planets and for space tourism. (ANI)